Piece of luggage

ABSTRACT

A piece of luggage ( 1 ) comprising a housing ( 2 ) with a front wall ( 3 ), a back wall ( 4 ), a top wall ( 5 ), a bottom wall ( 6 ) and side walls ( 7, 8 ). There is at least one pair of wheels, and at least two functional elements ( 10, 11, 12, 13, 14 ). The elements are chosen from the group consisting of a telescopic handle ( 10 ), at least one carrying handle ( 11 ), a longitudinal closure element ( 12 ), a logo element ( 13 ), and a lock element ( 14 ). For each of said at least two functional elements ( 10, 11, 12, 13, 14 ) a recess ( 15, 16, 17, 18, 19, 30 ) is provided in the housing ( 2 ), in which recess ( 15, 16, 17, 18, 19, 30 ) said functional elements ( 10, 11, 12, 13, 14 ) are positioned.

TECHNICAL FIELD

The present invention relates to a piece of luggage with enhanced functions according to the preamble of claim 1.

PRIOR ART

In the field of air travelling airlines have issued, as it is well known, size restrictions for luggage. When it comes to carry on luggage for example, airlines have usually specific size as well as weight restrictions. Suitcases which are known from prior do not address this issue and very often the suitcases are not constructed optimally.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a piece of luggage which overcomes the drawbacks of prior art. In particular which has enhanced properties in view of the size restrictions in air travel under the provision that the traveler can travel with more personal items.

This object is solved by the subject matter of claim 1. Accordingly a piece of luggage comprising a housing, at least one pair of wheels and at least two functional elements. The housing comprises a front wall, a back wall, a top wall, a bottom wall and side walls, wherein said front wall and said back wall forming major faces of the housing, wherein said side walls forming side faces of the housing and extend between the front wall and the back wall. The top wall and the bottom wall forming top and bottom ends of the housing and extend between the front wall and the back wall. Said at least one pair of wheels is preferably a pair of caster wheels. Said at least two functional elements are chosen from the group of a telescopic handle, and/or at least one carrying handle, and/or a longitudinal closure element, and/or a logo element and/or a lock element. For each of said at least two functional elements a recess is provided in said housing in which recess said functional elements are positioned.

Due to the arrangement of the recesses and the positioning of the functional elements within said recesses, the volume of the housing can be enhanced. In other words: as the functional components are embedded in said recesses, the functional components do not extend from the respective walls which means that the wall is to be considered as the outermost part rather than the functional element. The latter would be the case when the functional component is arranged on and extends from said walls. Therefore due to the allocation of the functional elements in recesses, the interior space of the housing can be enhanced in that the position of wall can be altered as compared with the position of the wall in prior art suitcases.

The term recess is to be understood as being a cavity extending from a wall surface towards the interior space of the housing. Hence the wall has a dimple or depression and provides a cavity. However, the recess does not provide a through opening through the respective wall. In fact the recess is limited and defined by the surface of the respective wall. The recess extends from the wall surface into the interior space of the housing, but is still a part of the wall providing said housing and delimiting the interior space of the housing. Hence the recess is at least partly surrounded by a part of said wall.

The term wall includes at least one of the walls as mentioned above, namely the front wall, the back wall, the top wall, the bottom wall and/or the side walls.

The depth of the recesses as seen from the wall from which the recess extends into the housing is such that the said functional elements that is arranged in said recess is preferably fully embedded in a stored position, but may extend out of this recess in a use position. This has the advantage that the functional elements can be stored in the stored position and when being used can be moved out of the recess. Hence, when it comes to the assessment of the size of the piece of luggage the functional element is placed in the stored position such that it will not influence the size of the piece of luggage.

The depth of the recess is the distance between the wall surface surrounding said recess at least partly and the wall surface in said recess.

In a preferred embodiment the housing is provided by means of a front shell and by means of a back shell which are connected to each other with said longitudinal closure element. The front shell comprises the front wall and parts of said side wall, parts of said top wall and parts of said bottom wall. The back shell comprises the back wall and parts of said side wall, parts of said top wall and parts of said bottom wall.

Preferably each of the back shell and the front shell enclose substantially the same volume. Alternatively the volumes may also be different.

In this preferred embodiment at least two recesses, preferably at least three or at least four or at least five recesses, are arranged in said front shell, wherein the recesses are arranged such that the recesses extend into at least two different walls of said walls.

Even more preferably the recesses extend into said five walls, namely into the front wall, the top wall, the bottom wall and the side walls.

With regard to this preferred embodiment the same applies to the back shell: Thereby at least two recesses, preferably at least three or at least four or at least five recesses, are arranged in said back shell, wherein the recesses are arranged such that the recesses extend into at least two different walls of said walls. Even more preferably the recesses extend into said five walls, namely into the back wall, the top wall, the bottom wall and the side walls.

Preferably said front shell and said back shell are made out of a plastic sheet by means of a thermoforming process, in particular deep drawing process. In this process preferably a vacuum force is used to draw the preheated plastic sheet towards the tool. This process has the advantage that it is possible to form said recesses for the functional elements in an efficient manner In particular in view of molded housings this procedure has the advantage that it becomes possible to provide said shells with the recesses in said walls without a complex molding tool. Furthermore it becomes possible to remove the tool of the thermoforming process via the opening that is delimited by the top wall, the bottom wall and the side walls.

Preferably said front shell is formed as one integral single piece and/or said back shell is formed as one integral single piece. Hence, each of the shell can be produced with one single step.

Preferably said recesses have the shape of an undercut, as viewed from the inside of the piece of luggage or said shells. This means that the thickness of the wall of the shell is preferably substantially constant. In particular in combination with the thermoforming process it is advantageous since such a process allows an efficient manufacturing procedure.

A preferred embodiment is characterized in that at least one of said recesses is arranged in the top wall and/or the bottom wall and in that at least one of said recesses is arranged in one of said side walls. The top wall or the bottom wall, respectively extends perpendicular to the side wall. Hence recesses are arranged on the longitudinal side which is provided by the side wall and the transverse side which is provided by the top wall and/or the bottom wall. The production of such an embodiment is particularly advantageous as the depth of the recesses in the top wall and/or the bottom wall as well as in said at least one side wall can be enhanced.

The depth of the recesses as mentioned herein is preferably dependent on the size of the functional element that is placed in the recess. Preferably the depth is larger than 5 Millimeters, in particular between 5 to 50 Millimeters, in particular between 10 to 45 Millimeters. The depth applies in particular to the preferred embodiment that is characterized in that at least one of said recesses is arranged in the top wall and/or the bottom wall and in that at least one of said recesses is arranged in one of said side walls.

In a very preferred embodiment exactly of a telescopic handle, two carrying handles, a longitudinal closure element, a logo element and a lock element are arranged, whereby for each of said functional element one recess is provided. Some of the recesses may be connected with each other.

In a preferred embodiment the volume of said housing which is defined by said walls is larger than 90%, in particular larger than 95% of a virtual cuboid that is defined by planes extending parallel to said walls and which are adjacent to the outermost parts of said front wall, back wall, top wall, and side walls and by the outermost parts of said pair of wheels. With such a configuration the volume of the housing or the interior space can be maximized further.

Preferably in said top wall one of said recesses is arranged in which recess one of said carrying handles is placed. The carrying handle does thereby preferably not extend above the surface of the wall surrounding said recess. Alternatively or in combination to the recess in said top wall one of said recesses is arranged in one of said side walls in which recess one of said carrying handles is placed. Thereby the carrying handle does preferably not extend above the surface of the wall surrounding said recess.

Preferably the recess in which said carrying handle is placed extends further lateral to and below said carrying handle such that said carrying handle can be grasped by a user. Hence the recess will be enlarged such that the carrying handle can be grasped by a user.

Preferably said lock element is placed in a recess that is arranged in one of said side walls and/or in the top wall and/or in the bottom wall.

Preferably a continuous recess extends in a circumferential manner around said housing in the top wall, the side walls and the bottom wall in which continuous recess said closure element is arranged. Therefore the closure element is also arranged in a recess and does not add any height to the respective walls. This enhances the volume of the interior space further.

Preferably said continuous recess opens out in said recess or said recesses in which said carrying handle is arranged and/or in said recess in which said lock element is arranged.

Preferably a recess in region in which the top wall adjoins the back wall is arranged in which recess said telescopic handle is arranged.

Preferably the longitudinal closing element is arranged such that the sidewalls, the top wall and the bottom wall are separated by means of the longitudinally extending closure element such as a zipper. The closure element extends preferably substantially fully around the circumference as defined by the sidewalls, the top wall and the bottom wall.

Preferably the closure element is arranged centrically between said front wall and said back wall, but it can also be arranged off-center closer to the back wall or the front wall.

In a still further recess it is possible to arrange the logo element. Such a recess is preferably provided in the front wall.

In a preferred embodiment all functional elements are embedded in recesses which means that the volume of the interior space can be enhanced to a maximum volume.

Preferably in the edge regions in which three of said walls adjoin each other the housing further comprises embossed sections which are embossed with regard to the major parts of at least some of said walls. With such an embossment the major surfaces of the housing can be protected since said embossed section act as spacer.

Preferably the front wall and/or the back wall comprises an embossment, which extends preferably fully over the transverse side of the respective wall. As the embossment in the edge regions, this embossment also enhances the stability of the housing.

The embossment as arranged in connection with the front wall and/or the back wall extends preferably at least partly into the side walls.

Preferably a groove extends at least partly along or around said embossed sections and/or at least partly along or around said embossment. Such a groove may enhance the stability further. Further the grooves serve to prevent that dividing line of the forming tool becomes visible as the grooves extend along said dividing line.

The height of the embossed section and/or the embossment is preferably in the range of or larger of the thickness of the wall.

Preferably the pair of wheels is a pair of caster wheels, wherein each of said caster wheels comprises a swivel axis and at least one wheel with a peripheral surface rotating around a rotation axis which rotation axis runs perpendicular to said swivel axis.

Preferably exactly one pair of wheels is arranged, wherein said one pair is arranged proximate to the back wall, wherein the bottom wall extends as seen from a bearing point at which said wheels is affixed to the housing with a curved surface partly around said wheel. Alternatively two pairs of wheels are arranged, wherein one of said two pairs is arranged proximate to one of the sidewalls and the other of said two pairs is arranged proximate to the other of said sidewalls, wherein the bottom wall extends as seen from a bearing point at which said wheels is affixed to the housing with a curved surface partly around said wheel. Hence the wheels are at least partly embedded in a recess which is provided by said curved surface. In other words: Said curved surface provides a cavity and therefore the wheels are positioned in this cavity and are embedded in said housing. In case two pairs of caster wheels are arranged said bottom wall extends into said space such the volume of the housing can be enhanced.

Preferably the swivel axis of a caster wheel intersects with the bottom wall. Preferably the swivel axis is mounted to the housing via the bearing point which is firmly attached to the housing or which is an integral part of the housing.

Preferably the longitudinal closing element extends over said curved surface between two neighbouring wheels. Hence the recess in which the longitudinal closing element is arranged extends in said curved surface.

Preferably the curved surface extends at least to a plane extending through the rotation axis of the wheel and perpendicular to front wall or the back wall or underneath a plane extending through the rotation axis and perpendicular to the front wall or the back wall. This has the effect that the volume can be enhanced.

Preferably the curved surface extends with substantially the same cross-section from the back wall to the front wall. This allows in particular that the wheel can freely swivel around its swivel axis.

Although a caster wheel is a preferred wheel, any other suitable wheel can also be used. Such a wheel is then connected at a bearing point to the bottom wall which then extends with a curved surface such that for the wheel a cavity is formed.

Preferably the bottom wall is curved in a concave manner between two pairs of wheels.

Thereby the mechanical stability of the bottom wall can be enhanced.

In a preferred embodiment the housing is provided by means of a front shell and by means of a back shell which are connected to each other with said longitudinal closing element. The front shell comprising the front wall and parts of said side wall, parts of said top wall and parts of said bottom wall and the back shell comprising the back wall and parts of said side wall, parts of said top wall and parts of said bottom wall.

A method to produce a piece of luggage according to the description above comprises a step of thermoforming, in particular deep drawing, in which step the housing is formed, in particular a front shell comprising the front wall and parts of said side wall, parts of said top wall and parts of said bottom wall and a back shell comprising the back wall and parts of said side wall, parts of said top wall and parts of said bottom wall.

Preferably the thermoforming tool used in said thermoforming process to provide the shape of the housing or the back shell and the front shell, respectively comprises a main part and at least in the region in which the edge region is formed a slider part which can be moved relative to the main part of the thermoforming tool. In the usual case four edges are present at each of the shells and therefore preferably four sliders are provided in the thermoforming tool. It is further preferably that two of said sliders are in connection with each other. The sliders are preferably connected to the main part via an inclined surface which is inclined to the direction of movement when the housing is removed from the thermoforming tool. With the slider parts it is possible to form the above mentioned recesses in the respective wall, in particular with the respective depths, as wall as undercuts.

Preferably a vacuum force provided by the thermoforming tool can be used to draw the pre-heated plastics sheet against the tool.

Preferably the above mentioned grooves extend along the separation between the thermoforming tool and the slider.

Preferably the housing is made out of plastics that is suitable for thermoforming. Such materials include but are not limited to polycarbonate, Acrylonitrile butadiene styrene, polypropylene or selfreinforced polypropylene.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described in the following with reference to the drawings, which are for the purpose of illustrating the present preferred embodiments of the invention and not for the purpose of limiting the same. In the drawings,

FIG. 1 shows a perspective view of a piece of luggage according to one embodiment of the present invention;

FIG. 2 shows a side view of the piece of luggage according to FIG. 1;

FIG. 3 shows a bottom view of the piece of luggage according to FIG. 1;

FIG. 4 shows a perspective section view of the piece of luggage according to FIG. 1;

FIG. 5 shows a perspective detail view of a logo element that is arranged in the piece of luggage according to FIG. 1;

FIG. 6 shows views of a telescopic handle that is arranged in the piece of luggage according to FIG. 1;

FIG. 7 shows a perspective detail view of a lock element that is arranged in the piece of luggage according to FIG. 1;

FIG. 8/9 shows a front shell and a back shell of a piece of luggage according to FIG. 1;

FIG. 10 shows a tool to provide the shells according to FIGS. 8 and 9.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a perspective view of a piece of luggage 1. The piece of luggage 1 comprises a housing 2 and at least one pair of wheels, here a pair of caster wheels 9. A pair of wheels 9 comprises two wheels 9, here two caster wheels.

In the present embodiment of the piece of luggage two pairs of caster wheels 9 are arranged. Therefore the piece of luggage can be moved on said two pairs of caster wheels 9.

The housing 2 of the piece of luggage 1 comprises a front wall 3, a back wall 4, a top wall 5, a bottom wall 6 and side walls 7, 8. The top wall is not shown in the figures. The front wall 3 and the back wall 4 form major faces of the housing 2, wherein the side walls 7, 8 form side faces of the housing 2 and extend between the front wall 3 and the back wall 4. The top wall 5 and the bottom wall 6 provide top and bottom ends of the housing 2 and extend between the front wall and the back wall 4. The side walls 7, 8 are also in connection with the bottom wall 6 and the top wall. The housing 2 limits an interior space in which the user can place the items to be carried.

The piece of luggage 1 comprises further at least two functional elements 10, 11, 12, 13, 14, which are chosen from the group of a telescopic handle 10 and/or at least one carrying handle 11 and/or a longitudinal closure element 12 and/or a logo element 13 and/or a lock element 14. In the present embodiment five functional elements are arranged, namely a telescopic handle 10, two carrying handles 11, a longitudinal closure element 12, a logo element 13 and a lock element 14. The at least two functional elements 10, 11, 12, 13, 14 are necessary to provide the piece of luggage 1 with certain functional structure in order to have elements with which the user can handle the piece of luggage.

For each of said at least two functional elements 10, 11, 12, 13, 14 a recess 15, 15, 17, 18, 19 is provided in said housing 2. The recess 15, 15, 17, 18, 19 serves to accommodate the functional elements. Each of the functional elements 10, 11, 12, 13, 14 are positioned or embedded in a recess 15, 16, 17, 18, 19, 30. Preferably one recess 15, 16, 17, 18, 19, 30 is arranged per functional element 10, 11, 12, 13, 14.

From the figures it becomes evident that the term “recess” is to be understood as being a depression or cavity which extends from a major surface of the respective wall 3, 4, 5, 6, 7, 8 into the housing 2 towards the interior space. Thereby the recess is also a part of the respective wall. This can be in particularly seen with regard to the logo element 13 in FIG. 1. The recess 30 for the logo element 13 extends from the major surface of the front wall. The major surface is designated with reference numeral 31.

The depth of the recess 15, 16, 17, 18, 19, 30 as seen from the major surface of the respective wall 3, 4, 5, 6, 7, 8 from which the recess 15, 16, 17, 18, 19, 30 extends into the housing 2 is such that said functional element 10, 11, 12, 13, 14 is preferably fully embedded. In particular the functional element 10, 11, 12, 13, 14 shall be fully embedded in the stored position. The stored position is the position in which the functional element 10, 11, 12, 13, 14 is not used, but remains fully embedded in the recess 15, 16, 17, 18, 19, 30. In a use position the functional element 10, 11, 12, 13, 14 may extend out of the recess. In particular the handles, namely the telescopic handle 10 and the carrying handle 11 extend in the use position out of the recess 15, 16, 17, 18, 19, 30, so that a user can easily grasp the telescopic handle 10 and the carrying handle 11. After use, in particular after transportation, the telescopic handle 10 and the carrying handle 11 can be stored again in their stored position such that they are fully embedded in the recess. In the figures all functional elements are shown as being in their stored position.

The volume of the housing 2 is defined by the walls 3, 4, 5, 6, 7, 8. This volume is preferably larger than 90 percent, in particular larger than 95 percent, of a virtual cuboid that is defined by planes extending parallel to said walls 3, 4, 5, 6, 7, 8 and which are adjacent to the outermost part of said front wall 3, back wall 4, top wall 5 and side walls 7, 8 and by the outermost parts of said pair of wheels 9. The outermost parts are the parts that extend from or are part of the walls 3, 4, 5, 6, 7, 8 and the housing 2 away, namely against the interior space. Those outermost parts are the most extreme parts of the housing 2 or the wheels 9. With such a volume in view of this virtual cuboid it is possible to have a maximum amount of volume of the interior space.

The virtual cuboid is preferably identical with the requirements of the airlines concerning the allowed luggage size. For example with regard to the carry-on luggage allowance in case the piece of luggage shall be carry-on luggage. Nevertheless it may also be possible that the piece of luggage 1 can be provided larger than a usual carry-on luggage.

As it can be seen form FIG. 1 in the top wall 5 there is a recess 15 arranged. In said recess 15 one of said carrying handles 11 is placed. The recess 15 extends thereby from the top wall 5 towards the interior space of the housing 2 and provides thereby a depression in the top wall 5 in which the carrying handle 11 is placed.

Furthermore in the present embodiment in one of said side walls, namely in side wall 7, a further recess 16 is arranged. In the recess 16 a further carrying handle 11 is placed. The recess 15 extends thereby into side wall 7 and provides a depression in which the carrying handle 11 is placed.

Both carrying handles 11, are arranged such that they do not extend as seen from the interior space of the housing 2 over the top wall or over the side wall 7 respectively. Therefore the carrying handles 11 are in their stored position fully embedded in the top wall 5 or the side wall, respectively which means that the do not extend out of the recess 15, 16.

Furthermore it can be seen from FIGS. 1, 2 and 4 that the recess 16 and 15 are slightly larger than the carrying handle 11. Namely the recesses 15, 16 extend lateral to as well as below said carrying handle 11. Thereby the recesses 15, 16 are arranged such that said carrying handle 11 can be grasped by the hand of a user. The user can grasp the carrying handle 11 by introducing its hand into the recess 15, 16 and in particular under the handle 11.

In the present embodiment a further recess is arranged in the side wall 7. This recess is designated with the reference number 17 and serves to accommodate the locking element 14. With the locking element 14 it is possible to provide a lock for the longitudinal closure element 12. In the present case the longitudinal closure element 12 is a zipper having to sliders 29 which sliders 29 can be connected to the lock element 14. As the other functional element the lock element 14 is also fully embedded in the recess 17. This means that no parts of the locking element extends over and above the side wall 7, as the lock element 14 is fully embedded in the recess 17.

As it can be seen from FIG. 1 a further recess 18 is arranged. The recess 18 is a continuous recess, that extends in a circumferential manner around said housing 2 in the top wall 5, the side walls 7, 8 and the bottom wall 6. In said continuous recess 18 said longitudinal closure element 12 is arranged and extends also continuously in a circumferential manner around said housing 2. Thereby it can encompass the housing 2 fully or it can be interrupted in one of said walls, preferably in said bottom wall 6. As mentioned above the longitudinal closure element 12 is preferably a zipper.

The longitudinal closure element 12 extends in said continuous recess 18 and does not extend as seen from the interior space of the housing 2 over and above the top wall 5, the side walls 7, 8 and the bottom wall 6. It is fully embedded in said recess 18. As it can be seen in the view of FIG. 2 the respective walls 5, 6, 7, 8 have in the cross section a gap which provides this continuous recess 18.

The longitudinal closure element 12 provides a link between the front shell 24 and the back shell 25, both of which forming the housing 2. The front shell 24 is provided by means of the front wall 3, parts of the top wall 5, parts of the bottom wall 6 and parts of the side walls 7, 8. Similarly the back shell 25 is provided by the back wall 4, parts of the top wall 5, parts of the bottom wall 6 and parts of the side walls 7, 8. On both shells 24, 25 the longitudinal closure elements 12 is connected to the parts of the top wall 5, the bottom wall 6 and the side walls 7, 8 which are allocated to the respective front wall 3 or back wall 4. Hence the continuous recess 18 is part of the front shell 24 and the back shell 25.

As it can be seen from FIG. 1 the continuous recess 18 opens out in said recess or said recesses 15, 16 in which said carrying handle 11 is arranged. Alternatively or additionally the continuous recess 18 opens out in said recess 17 in which said lock element 14 is arranged. The latter is particularly advantages as than the sliders 29 can easily be guided to the lock element 14 which is detailed in FIG. 7.

From FIG. 4 it becomes evident that still a further recess 19 is arranged in a region in which the top wall 5 adjoins the back wall 4. In this recess 19 the telescopic handle 10 is arranged. As with the other functional elements the telescopic handle 10 remains in its stored position fully embedded in the recess 19 but extends out of said recess 19 when being used.

FIG. 5 shows further that the logo element 13 that is arranged in recess. The logo element 13 is preferably placed in the front wall 3 such that it can be easily recognized. This means that the recess 30 in which the logo element 13 is placed is also arranged in the front wall.

With the aid of FIG. 4 the edge region 20 of the housing 2 will now be explained in more details. In the edge region 20 in which three of said walls 3, 4, 5, 6, 7, 8 adjoin each other the housing 2 further comprises embossed sections 21. Thereby the embossed section 21 extends in each of the walls 3, 4, 5, 6, 7, 8. It is also possible that the embossed sections 21 extend only into one or two of said walls 3, 4, 5, 6, 7, 8. The embossed sections 21 are embossed with regard to the major parts of said walls 3, 4, 5, 6, 7, 8. The major parts are considered as being these parts which have the largest surface. The height of the embossed sections 21 is preferably around the thickness of the walls 3, 4, 5, 6, 7, 8. The embossed sections 21 enhance the stability of the housing 2. The embossed sections 21 can provide the above mentioned outermost parts in order to determine the virtual cuboid.

Furthermore from FIG. 1 it can be seen that also the front wall 3 and the back wall 4 comprises an embossment 22. This embossment 22 extends fully over the transverse side of the respective wall 3, 4 and is preferably arranged centrically. With regard to the height of the embossment 22 the same can be said as with regard to the height of the embossed sections 21. The embossment 22 extends partly into the side walls 7, 8.

Furthermore it can be recognized from FIG. 1 that in the present embodiment a groove 23 is arranged. The groove 23 extends at least partly along or around said embossed sections 21 and or at least party along or around said embossment 22. With the groove 23 the stability of the housing 2 can be further enhanced.

FIGS. 8 and 9 show the front shell 24 and the back shell 25 without the functional elements 10, 11, 12, 13, 14, 15. Thereby reference is made to the above mentioned description which shall be applied on these figures.

In the present embodiment, as it can be seen from FIGS. 1 to 3 two pairs of caster wheels 9 are arranged. One of said pairs of caster wheels 9 is arranged proximate to one of the side walls 7 and the other of said pairs of caster wheels 9 is arranged proximate to the other side wall 8. This means that the piece of luggage 1 stands on four caster wheels 9. Each of the caster wheels 9 has, as explained above, in the present embodiment two wheels 10 which are connected with each other through the rotation axis R. The wheels can further swivel around a swivel axis S.

The bottom wall 6 extends as seen from the bearing point 32 at which said swivel axis S intersects the bottom wall 6 with a curved surface 33 partly around said wheel 9. The curved surface 33 provides a recess in which the caster wheels 9 are placed. Thereby the volume of the piece of luggage 1 can be enhanced as the housing 2 extends in a region between the two pairs of caster wheels 9. This region is shown in FIG. 2 with the reference numeral 34. This curved surface 33, which is in fact a part of the bottom wall 6 links the parts of the bottom wall 6 between the wheels 9 with the side wall 7, 8.

The curved surface 33 extends at least to a plane E or under said plane E. The plane E is defined as extending through the rotation axis R of the caster wheels 9 and perpendicular the front wall 3 or the back wall 4. In the present embodiment parts of the curved surface 13 extend under said plane as seen from the main part of the housing 2.

In particular when the piece of luggage is a carry on luggage the following applies: The curved surface 33 extends substantially with the same cross action from the back wall 4 to the front wall 3. Thereby a curved space or recess 35 is provided in which said caster wheel 9 can freely rotate. With other words the curved surface 33 extends around an axis which runs perpendicular to the front wall 3 and the back wall 4. Said axis is preferably collinear with the rotation axis R in case the rotation axis R runs perpendicular to the front wall 3 and the back wall 4.

In the preferred embodiment as shown in FIG. 1 the bottom wall 6 is also curved. The curvature is designated with reference sign 35. Thereby the bottom wall 6 is curved with curvature 35 in a concave manner between the two pairs of caster wheels 9. This has the advantage that the ground clearance between a ground on which the piece of luggage 1 stands with the peripheral surface 11 and the bottom wall can be enhanced under the provision of maximising the volume.

FIG. 10 shows a tool to manufacture the housing 2 by means of a thermoforming, in particular of a deep drawing process. According to a method of the present invention the housing 2 is manufactured by a method which comprises a step of thermoforming, in particular deep drawing in which step the housing 2 is formed. In particular the front shell 24 and the back shell 25 are formed individually. As it can be seen the thermoforming tool 26 comprises a main part 27 and a slider part 28. The slider part 28 can be moved with regard to the main part 27. This allows forming of undercuts as it can be seen in FIGS. 8 and 9.

The slider part 28 serves to produce the above mentioned edge regions 20 and the associated embossed sections 21.

LIST OF REFERENCE SIGNS 1 piece of lugagge 2 housing 3 front wall 4 back wall 5 top wall 6 bottom wall 7 side wall 8 side wall 9 caster wheel 10 telescopic handle 11 carrying handle 12 closure element 13 logo element 14 lock element 15 recess in top wall 16 recess in sidewall 17 recess for lock 18 continuous recess 19 recess for telescopic handle 20 edge region 21 embossed section 22 embossment 23 groove 24 front shell 25 back shell 26 thermoforming tool 27 main part 28 slider part 29 slider 30 recess for logo element 31 major surface 32 bearing point 33 curved surface 34 region 35 curvature R Rotation axis S Swivel axis 

1. A piece of luggage comprising a housing with a front wall, a back wall, a top wall, a bottom wall and side walls, wherein said front wall and said back wall forming major faces of the housing, wherein said side walls forming side faces of the housing and extend between the front wall and the back wall and wherein said top wall and said bottom wall forming top and bottom ends of the housing and extend between the front wall and the back wall; at least one pair of wheels; and at least two functional elements, which are chosen from the group of at least one of a telescopic handle, and at least one carrying handle, and a longitudinal closure element, and a logo element and a lock element, wherein for each of said at least two functional elements a recess is provided in said housing in which recess said functional elements are positioned.
 2. The piece of luggage according to claim 1, wherein depth of the recesses as seen from the wall from which the recess extends into the housing is such that the said functional element is fully embedded in their stored position, but may extend out of this recess in a use position.
 3. The piece of luggage according to claim 1, wherein the housing is provided by means of a front shell and by means of a back shell which are connected to each other with said longitudinal closure element, wherein the front shell comprising the front wall and parts of said side wall, parts of said top wall and parts of said bottom wall and the back shell comprising the back wall and parts of said side wall, parts of said top wall and parts of said bottom wall.
 4. The piece of luggage according to claim 3, wherein at least two recesses are arranged in said front shell, wherein the recesses are arranged such that the recesses extend into at least two different walls of said walls.
 5. The piece of luggage according to claim 3, wherein at least two recesses are arranged in said back shell, wherein the recesses are arranged such that the recesses extend into at least two different walls of said walls.
 6. The piece of luggage according to claim 3, wherein said front shell and said back shell are made out of a plastic sheet by means of a thermoforming process.
 7. The piece of luggage according to claim 4, wherein at least one of said front shell is formed as one integral single piece and said back shell is formed as one integral single piece.
 8. The piece of luggage according to claim 1, wherein at least one of said recesses is arranged in at least one of the top wall and the bottom wall and wherein at least one of said recesses is arranged in one of said side walls.
 9. The piece of luggage according to claim 1, wherein the volume of said housing which is defined by said walls is larger than 90% of a virtual cuboid that is defined by planes extending parallel to said walls and which are adjacent to the outermost parts of said front wall, back wall, top wall, and side walls and by the outermost parts of said pair of wheels.
 10. The piece of luggage according to claim 1, wherein at least one of in said top wall one of said recesses is arranged in which recess one of said carrying handles is placed and in one of said side walls one of said recesses is arranged in which recess one of said carrying handles is placed.
 11. The piece of luggage according to claim 10, wherein the recess extends further lateral to as well as below said carrying handle such that said carrying handle can be grasped by a user.
 12. The piece of luggage according to claim 1, wherein at least one of in one of said side walls and in the top wall and in the bottom wall a recess is arranged in which recess said lock element is placed.
 13. The piece of luggage according to claim 1, wherein a continuous recess extends in a circumferential manner around said housing in the top wall, the side walls and the bottom wall in which continuous recess said closure element is arranged.
 14. The piece of luggage according to claim 1, wherein said continuous recess opens out at least one of in said recess or said recesses in which said carrying handle is arranged and in said recess in which said lock element is arranged.
 15. The piece of luggage according to claim 1, wherein a recess in a region in which the top wall adjoins the back wall is arranged in which recess said telescopic handle is arranged.
 16. The piece of luggage according to claim 1, wherein in the edge regions in which three of said walls adjoin each other the housing further comprises embossed sections which are embossed with regard to the major parts of at least some of said walls.
 17. The piece of luggage according to claim 1, wherein at least one of the front wall and the back wall comprises an embossment.
 18. The piece of luggage according to claim 16, wherein a groove extends at least partly along or at least one of around said embossed sections and at least partly along or around said embossment.
 19. The piece of luggage according claim 1, wherein exactly one pair of wheels is arranged, wherein said one pair is arranged proximate to the back wall, wherein the bottom wall extends as seen from a bearing point at which said wheels is affixed to the housing with a curved surface partly around said wheel, or wherein two pairs of wheels are arranged, wherein one of said two pairs is arranged proximate to one of the sidewalls and the other of said two pairs is arranged proximate to the other of said sidewalls, wherein the bottom wall extends as seen from a bearing point at which said wheels is affixed to the housing with a curved surface partly around said wheel.
 20. The piece of luggage according to claim 19, wherein the curved surface extends at least one of at least to or underneath a plane extending through the rotation axis and perpendicular to the back wall or the front wall, and the curved surface extends with substantially the same cross-section from the back wall to the front wall and the bottom wall is curved with a curvature in a concave manner between two pairs of wheels.
 21. A method to produce a piece of luggage according to claim 1, wherein the method comprises a step of thermoforming, in which step the housing is formed.
 22. The method according to claim 21, wherein the thermoforming tool used in said thermoforming process to provide the shape of the housing comprises a main part and at least in the region in which the edge region is formed a slider part which can be moved relative to the main part of the thermoforming tool.
 23. The piece of luggage according to claim 1, wherein the at least one pair of wheels corresponds to at least one pair of caster wheels.
 24. The piece of luggage according to claim 4, wherein at least three or at least four or at least five recesses are arranged in said front shell.
 25. The piece of luggage according to claim 5, wherein at least three or at least four or at least five recesses are arranged in said back shell.
 26. The piece of luggage according to claim 6, wherein said front shell and said back shell are made out of a plastic sheet by means of a deep drawing process.
 27. The piece of luggage according to claim 9, wherein the volume of said housing is larger than 95%.
 28. The piece of luggage according to claim 13, wherein said continuous recess has a depth of larger than 5 Millimeters.
 29. The piece of luggage according to claim 17, wherein the embossment extends at least one of fully over the transverse side of the respective wall and at least partly into the side walls.
 30. The method according to claim 21, wherein at least one of the step of thermoforming corresponds to deep drawing and in which step a front shell comprising the front wall and parts of said side wall, parts of said top wall and parts of said bottom wall and a back shell comprising the back wall and parts of said side wall, parts of said top wall and parts of said bottom wall are formed. 